This invention pertains generally to nickel batteries, such as nickel-zinc and nickel-metal hydride batteries. More specifically, this invention pertains to compositions and manufacturing methods for positive nickel electrodes.
Recent economic trends have unmistakably indicated a need for high power and high energy density rechargeable batteries, particularly for applications such as electric vehicles and power tools. Certain aqueous batteries employing a nickel hydroxide electrode may provide suitably high energy density and even high power to meet this need. The nickel hydroxide electrode has been used as the positive electrode in nickel-metal hydride batteries, nickel-cadmium batteries and nickel-zinc batteries. The electrode typically includes nickel hydroxide (including its oxidized form nickel oxyhydroxide), nickel powder and binding materials. Cobalt metal and/or a cobalt compound may be included to increase the conductivity of the nickel electrode. Unfortunately, cobalt can under certain conditions move to the negative electrode where it can promote hydrogen evolution and related difficulties, particularly in the high power nickel-zinc battery.
As demands for higher power and energy density escalate, the composition and associated manufacturing methods of nickel hydroxide electrodes become ever more significant.